Component Embedded in Component Carrier and Having an Exposed Side Wall

ABSTRACT

A component carrier including a stack with a plurality of electrically insulating layer structures and/or a plurality of electrically conductive layer structures, and a component embedded in the stack, wherein at least a portion of a side wall of the component is exposed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the filing date of EuropeanPatent Application No. 17185037.3, filed 4 Aug. 2017, the disclosure ofwhich is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments of the invention relate to a method of manufacturing acomponent carrier, and to a component carrier.

BACKGROUND

In the context of growing product functionalities of component carriersequipped with one or more electronic components and increasingminiaturization of such electronic components as well as a rising numberof electronic components to be mounted on the component carriers such asprinted circuit boards, increasingly more powerful array-like componentsor packages having several electronic components are being employed,which have a plurality of contacts or connections, with ever smallerspacing between these contacts. Removal of heat generated by suchelectronic components and the component carrier itself during operationbecomes an increasing issue. At the same time, component carriers shallbe mechanically robust and electrically reliable so as to be operableeven under harsh conditions. Moreover, an extended functionality ofcomponent carriers with embedded component is demanded by users.

SUMMARY

There may be a need to integrate a component in a component carrier in away to allow for an efficient and reliable operation while enabling ahigh degree of functionality.

To address this need and perhaps other needs, a method of manufacturinga component carrier, and a component carrier according to theindependent claims are provided.

According to an exemplary embodiment, a component carrier is providedwhich comprises a stack comprising a plurality of electricallyconductive layer structures and/or electrically insulating layerstructures, and a component embedded in the stack, wherein at least aportion of a side wall of the component is exposed (for instance withregard to an environment of the component carrier).

According to another exemplary embodiment, a method of manufacturing acomponent carrier is provided, wherein the method comprises forming astack of a plurality of electrically conductive layer structures and/orelectrically insulating layer structures, embedding a component in thestack, and subsequently removing material of the stack to thereby exposeat least a portion of a side wall of the component.

Overview of Embodiments

In the context of the present application, the term “component carrier”may particularly denote any support structure which is capable ofaccommodating one or more components thereon and/or therein forproviding mechanical support and/or electrical connectivity. In otherwords, a component carrier may be configured as a mechanical and/orelectronic carrier for components. In particular, a component carriermay be one of a printed circuit board, an organic interposer, and an IC(integrated circuit) substrate. A component carrier may also be a hybridboard combining different ones of the above mentioned types of componentcarriers.

In the context of the present application, the term “embedded component”may particularly denote any body or member not in the shape of andhaving a lower dimension than the layer structures of the layer stackand being nevertheless accommodated in an interior of component carriermaterial (i.e. stack material, for instance resin with reinforcingparticles as dielectric material and copper as electrically conductivematerial). The accommodation of the component in the component carriermaterial may be accomplished by lamination, i.e. the application ofpressure and/or heat for integrally connecting the constituents of thecomponent carrier.

In the context of the present application, the term “exposed side wall”may particularly denote a lateral side wall portion of the componentembedded in component carrier material, which lateral side wall portionis not covered by component carrier material, in particular is notcovered at all with solid material. Thereby, an exposed side wall of thecomponent may form part of an exposed surface of the component carrieras a whole. When the component carrier is shaped as a plate with twoopposing main surfaces and a circumferential edge, the side wall mayform part of or may be substantially parallel to the circumferentialedge and may be perpendicular to the main surfaces of the componentcarrier.

According to an exemplary embodiment, a component carrier with anembedded component is provided which is exposed laterally, i.e. at itsside wall. This can be accomplished in a highly accurate way by removingmaterial of a stack of connected layer structures in which the componentis embedded after the embedding procedure is completed to thereby exposethe lateral side surface. But taking this measure, it becomes possibleto functionally use a side wall of a component for establishing aconnection or coupling with an environment, for instance for sensor oroptoelectronic applications. The upper and lower main surfaces of thestack and hence of the component carrier may thereby remain availablefor mounting further components, etc. The described architecture therebyrenders it possible to keep component carriers compact withoutcompromising on the functionality thereof. In contrast to this, alateral side surface of the component carrier may be made available as afunctional part of the component.

In the following, further exemplary embodiments of the method and thecomponent carrier will be explained.

In an embodiment, the exposed side wall and a side wall of the stack arealigned to form a substantially continuous (for instance substantiallyvertical) side wall of the component carrier. In other words, it ispossible that the exposed side wall of the component and the side wallof the stack are aligned with one another or are in flush with oneanother. This prevents undercuts at the side wall of the componentcarrier in which contaminants such as dust may accumulate.

In another embodiment, an access recess exposing the side wall extendslaterally from a lateral side wall of the stack up to the lateral sidewall of the component. In such an embodiment, it is possible to spacethe exposed side wall of the component with regard to the side wall ofthe component carrier. Such an architecture may for instance beadvantageous when a mechanical, an optical, an electrical or anelectro-optical coupling of the exposed component with a periphery shallbe established via an electric or optical cable. For instance, anelectric lead or an optical fiber may be inserted into the access recessso as to establish an electric, optical and/or electro-optical coupling.

In another embodiment, an access recess exposing the side wall extendsfrom one of two opposing main surfaces of the stack up to the component.In other words, the access recess may be formed as a (blind or through)hole which may extend from one of the two opposing main surfaces atleast up to the embedded component or even up to the other main surface.In such an embodiment, the embedded component remains securelymechanically protected in the interior of the stack while neverthelessbeing functionally coupled to an exterior environment of the componentcarrier. For instance, such an embodiment may be used for a gas,chemical or moisture sensor having its sensitive surface at the exposedside wall of the component.

In an embodiment, the access recess is a slit extending into a centralportion of the stack. Preferably, the slit has a length being largerthan a width, For instance, the length may be at least twice thedistance of the width. Such a slit may have a length being significantlylonger than (in particular at least five times of) than a width. Thelonger extension direction of the slit may correspond to a horizontalextension direction of the side wall of the component, whereas the shortextension direction may extend perpendicular to the side wall of thecomponent. Such a slit may be simply formed by drilling, milling orlaser cutting perpendicular to a main surface of the component carrier.

In an embodiment, the access recess is configured as one of the groupconsisting of a through-hole extending through the entire stack, and ablind hole.

In an embodiment, only one main surface of the, in particularsubstantially cuboid, component is exposed. In other words, five mainsurfaces of the substantially cuboid component may remain covered bycomponent carrier material of the component carrier and may thus beproperly mechanically protected. The, in this case only, one side wallbeing exposed may then allow precisely defining the interface propertiesbetween the component and the environment.

In an embodiment, the component is arranged laterally asymmetrically inan accommodation cavity of the stack, in particular with differentdistances with regard to opposing accommodation cavity delimiting sidewalls of the stack. This has the advantage that the side of the cavitywith the smaller distance to the component serves for securely definingthe position of the component in the component carrier (for instance byconstituting a lateral abutment surface for the component), wherein theother side wall of the cavity with the larger distance to the componentallows exposing the side wall of the component even by processing withrelatively low spatial accuracy. In other words, the larger distancevalue corresponds to a tolerance allowed when exposing the side wall ofthe component by cutting through the larger distance.

In an embodiment, the component comprises a sensor configured forsensing sensor information via the exposed surface. In other words, theexposed surface may comprise at least a sensitive portion for detectinga medium to be sensed. Such a medium may be electricity, electromagneticradiation (in particular optical light), or a substance (such as a gas,a liquid, or any other chemical). Thus, exposing the lateral side wallor surface of the component allows manufacturing a component carrierwith integrated sensor functionality in a compact way.

In an embodiment, the component comprises an electromagnetic radiationsource configured for emitting electromagnetic radiation via the exposedsurface. In such an embodiment, the component carrier may be capable ofgenerating electromagnetic radiation transmitted via the exposed surfacetowards an environment or a communication partner device (for instance areceiver). For example, the component may be a laser diode or any otherlight source.

In an embodiment, the component carrier comprises a further componentembedded in the stack, wherein the component and the further componentare communicatively coupled, in particular at least partially via theaccess recess. For instance, the further component may be coupled to thepreviously mentioned component via the access recess. For example, oneof the component and the further component may be a sender (for instancea light sender) and the other one of the component and the furthercomponent may be a receiver (for instance a light receiver).

In an embodiment, the component and the further component are configuredas a pair of an electromagnetic radiation emitter (for instance capableof generating electromagnetic radiation in the visible, infrared and/orUV range) and an electromagnetic radiation detector (for instancecapable of sensing electromagnetic radiation in the visible, infraredand/or UV range), a pair of a light guide (such as a light fiber) and alight emitter (such as a laser diode), or a pair of a light guide (suchas a light fiber) and a light detector (such as a photodiode).

In an embodiment, at least one of the electrically insulating layerstructures being in direct contact with or being neighbored to theembedded component (in particular being arranged directly above and/ordirectly below the component) is made of low-flow prepreg or no-flowprepreg. However, FR4 material may also be used. Advantageously, no-flowprepreg or low-flow prepreg will not or substantially not re-melt/notbecome flowable during lamination, so that a hole next to the componentwill not be closed during laminating by liquefied resin or the like andthe side wall to be exposed can be kept free of resin material. Whenlaminating a corresponding stack by applying mechanical pressure and/orheat, the material of the low-flow prepreg or no-flow prepreg isadvantageously prevented from flowing into a hollow space betweencomponent and layer stack. By subsequently exposing the side wall of thecomponent by removing (for instance cutting) a portion of the stackadjacent to the hollow space, it is possible to complete formation ofthe component carrier with embedded component having an exposed sidewall. This procedure simplifies exposing the side wall of the component,for instance by milling.

In an embodiment, embedding the component in the stack comprisesarranging the component in direct contact with a plurality ofelectrically conductive layer structures and/or electrically isolationlayer structures such that at least five surfaces of the component arecovered by the stack. Thereby, an orientation of the component with thestack can be made more precise and/or a sensitivity of the componentwith respect to external impacts can be decreased.

In an embodiment, embedding the component in the stack comprises formingan accommodation cavity (i.e. a hollow space for mounting the component)in at least one of the layer structures of the stack and placing thecomponent in the accommodation cavity. The latter mentioned placementmay be made asymmetrically in a lateral direction so that two opposinggaps between component and respective side walls of the stack havedifferent sizes. The accommodation cavity may be formed, for example, byusing a pre-cut core, by mechanically drilling or laser drilling, or byapplying the concept of release layers. Such a release layer may be alayer (for instance made of a waxy material) on which other componentcarrier material of the stack does not properly adhere. Cutting acircumferentially closed hole above such a release layer may thereforeallow removal of a piece of the stack above the release layer to therebycomplete formation of the cavity.

In an embodiment, the component is placed in the accommodation cavity sothat a size of a gap between a side wall of the component and anaccommodation cavity delimiting side wall of the stack is different froma further size of a further gap between an opposing further side wall ofthe component and an opposing further accommodation cavity delimitingside wall of the stack. At a side wall of the component which shall notbe exposed after embedding, the size of the gap shall be as small aspossible so as to precisely define the position of the component in thecomponent carrier. In contrast to this, at an opposing other side wallof the component which shall be exposed later the dimension of the gapmay be advantageously larger so that the accuracy of removing materialfor exposing the component on the corresponding side thereof need not bevery high. This relaxes the requirements of spatial accuracy duringstack material removal in terms of exposing the side wall.

In an embodiment, the method further comprises filling at least part ofa gap between the component and an accommodation cavity delimiting sidewall of the stack with a removable sacrificial material, and at leastpartially removing the sacrificial material after completion of theembedding, in particular to thereby expose the side wall. In thiscontext, the term “sacrificial material” may particularly denote anauxiliary material which is provided only for temporary use and whichshall later be intentionally removed so that it does not form part ofthe final product, i.e. component carrier. In the present embodiment,the sacrificial material is provided for preventing the component frommigrating within the cavity, because a free gap of the cavity may befilled with the sacrificial material. The sacrificial material maytemporarily cover the side wall to be exposed later, but may be easilyremovable from this side wall. The sacrificial material may thus havethe property of being easily removable selectively with regard to thecomponent material so that the sacrificial material can be later removedfor exposing the side wall of the component without harming thecomponent and without the need to apply a complex removal procedure.

In an embodiment, the method further comprises inserting the componentin a first part of the accommodation cavity, and subsequently fillingthe sacrificial material into at least part of a remaining second part(as the gap) of the accommodation cavity laterally juxtaposed to thefirst part. Thus, the component may firstly be placed in theaccommodation cavity, and a remaining gap may be filled partially orentirely with the sacrificial material, for instance using a wiper. Thisembodiment has the advantage that a single cavity formation process issufficient to provide an accommodation volume for both the sacrificialmaterial and the component.

In an alternative embodiment, the method further comprises forming afirst cavity portion (which may later constitute the gap) in the stackand filling the first cavity portion at least partially with thesacrificial material. Subsequently, a second cavity portion may beformed separately in the stack and overlapping with the first cavityportion. In other words, the second cavity portion may be composed ofpart of the first cavity portion and of an adjacent portion of the stackwhich is removed. It is then possible to insert the component into thesecond cavity portion so that the first cavity portion at leastpartially filled with the sacrificial material and the second cavityportion accommodating the component together constitute theaccommodation cavity. Thus, it is possible that a first cavity (or firstcavity portion of the accommodation cavity) is formed in the stack andis filled with the sacrificial material, for instance using a wiper.Optionally, the sacrificial material may then be cured. It is thenpossible to form, thereafter and separately, a second cavity (or secondcavity portion of the accommodation cavity) which partially overlapswith the first cavity. In this context, it is also possible to remove aportion of the sacrificial material in the overlapping volume. Thecomponent may then be placed in the second cavity. An advantage of suchan embodiment is that the process of applying the sacrificial materialis simplified and rendered more accurate, since it can be applied in afirst cavity portion of relatively large size, and not limited to asmall gap between component and side wall of the stack next to thecavity. Another advantage of such an approach is that a potential curingprocess for curing the sacrificial material may be carried out prior tothe insertion of the component, so that the component is not harmed bycuring conditions (for instance an elevated temperature).

In an embodiment, the sacrificial material comprises one of the groupconsisting of a release structure with non-adhesive properties withregard to the material of the stack and the component, an evaporableliquid, a liquid which can be flushed out, and a substance which can bedissolved (for instance by water or an aqueous solution). Such a releasestructure may for instance be made of a waxy material or may be based onpolytetrafluoroethylene. A suitable evaporable liquid is water oralcohol. A liquid which can be flushed out can be substantially anyliquid which may be later removed from the gap to thereby expose theside wall by applying pressurized gas, etc.

In an embodiment, the method further comprises providing the componentwith a removable sacrificial material thereon, in particular a releasestructure, prior to the embedding, subsequently embedding the componentwith the removable sacrificial material thereon into the stack, and atleast partially removing the sacrificial material after completion ofthe embedding, in particular to thereby expose the side wall. Thus, itis also possible to apply a release layer or another sacrificialmaterial directly on the component before initiating the embeddingprocedure. This renders it dispensable to apply a sacrificial materialin a tiny gap.

In an embodiment, removing the material of the stack comprises at leastone of a group consisting of milling and laser cutting. For instance, anedge section of the component carrier may be removed by milling or lasercutting to thereby expose the side wall of the component.

In an embodiment, a size of a lateral gap between the component and anaccommodation cavity delimiting side wall of the stack is at least 50μm, in particular at least 300 μm, more particularly at least 500 μm.For instance, the size of the lateral gap may be in a range between 5 μmand 500 μm. This allows carrying out the material removing procedurewith low accuracy requirements.

In an embodiment, embedding the component comprises laminating thecomponent with the stack so that at least partially uncured material ofthe layer structures is cured. Curing may for instance be established bypressurising and heating curable resin which thereby starts crosslinking. During the curing, the resin temporarily melts, flows into tinygaps, re-solidifies, and thereby interconnects the various constituentsof the component carrier. Thereby, a mutual integral connection betweenthe stack and the component can be ensured, and consequently a highmechanical integrity of the component carrier as a whole.

In an embodiment, forming the stack comprises attaching a temporarycarrier to the layer structures when the latter are still in a conditionto comprise at least partially uncured material. In an embodiment, thetemporary carrier comprises a sticky surface facing the componentcarrier material and the recess or cavity. Providing the temporarycarrier with a sticky surface simplifies connection of the temporarycarrier on the component carrier material, in particular a core having athrough-hole, closed by the temporary carrier. In an embodiment, thetemporary carrier comprises a rigid plate. It is advantageous that thetemporary carrier has a rigid plate providing the semifinished productstill including the temporary carrier with additional stability during alamination procedure by which further layers are built up. However, asan alternative to a rigid plate (preferably having a sticky uppersurface), it is also possible that the temporary carrier is a stickyfoil or tape being flexible.

In an embodiment, it is possible to remove the temporary carrier fromthe stack after curing the at least partially uncured material of thelayer structures. Since after curing, the previously uncured materialhas been cured and hardened, the provision of mechanical support by thetemporary carrier may be dispensable after completion of the laminationand curing procedure. For instance, the temporary carrier may be simplypeeled off from the semifinished product after lamination.

In an embodiment, the component comprises an electromagnetic radiationemitting member (such as a light-emitting diode) configured for emittingelectromagnetic radiation (such as visible light), more specifically viaa side surface thereof, and being at least partially covered by anoptically transparent (in particular transparent in the visible range)material at least partially forming the exposed side wall and beingtransparent for the electromagnetic radiation emitted by theelectromagnetic radiation emitter member. The transparent material mayfor instance encapsulate the electromagnetic radiation emitter memberand may therefore simultaneously protect the latter while at the sametime enabling propagation of electromagnetic radiation through thetransparent material out of the component carrier via a side wallthereof. Preferably, the transparent material may be a resin (beingproperly compatible with other component carrier material of the stack)being free of fibers (which might deteriorate the undisturbedpropagation of the electromagnetic radiation) or the like.

In an embodiment, at least part of the transparent material at leastpartially forming the exposed side wall is polished. Polishing theexposed sidewall of the transparent material to decrease roughnessthereof has the particular advantage that undesired diffractionprocesses at the transition area between transparent material andsurrounding of the component carrier can be strongly suppressed. Such ascattering may unintentionally and undesirably increase across-sectional area of the propagating beam of electromagneticradiation, which may involve losses. However, diffraction may besuppressed by polishing the planar exposed sidewall, and a substantiallyparallel light beam may propagate out of the component carrier withreduced losses.

The mentioned component, and optionally at least one further componentto be surface mounted on or embedded in the component carrier, can beselected from a group consisting of an electrically non-conductiveinlay, an electrically conductive inlay (such as a metal inlay,preferably comprising copper or aluminum), a heat transfer unit (forexample a heat pipe), a light guiding element (for example an opticalwaveguide or a light conductor connection), an electronic component, orcombinations thereof. For example, the component can be an activeelectronic component, a passive electronic component, an electronicchip, a storage device (for instance a DRAM or another data memory), afilter, an integrated circuit, a signal processing component, a powermanagement component, an optoelectronic interface element, a voltageconverter (for example a DC/DC converter or an AC/DC converter), acryptographic component, a transmitter and/or receiver, anelectromechanical transducer, a sensor, an actuator, amicroelectromechanical system (MEMS), a microprocessor, a capacitor, aresistor, an inductance, a battery, a switch, a camera, an antennastructure, a logic chip, a light guide, and an energy harvesting unit.However, other components may be embedded in the component carrier. Forexample, a magnetic element can be used as a component. Such a magneticelement may be a permanent magnetic element (such as a ferromagneticelement, an antiferromagnetic element or a ferrimagnetic element, forinstance a ferrite coupling structure) or may be a paramagnetic element.However, the component may also be a further component carrier, forexample in a board-in-board configuration. The component may be surfacemounted on the component carrier and/or may be embedded in an interiorthereof. Moreover, also other components may be used as component.

In an embodiment, the component carrier comprises a stack of at leastone electrically insulating layer structure and at least oneelectrically conductive layer structure. For example, the componentcarrier may be a laminate of the mentioned electrically insulating layerstructure(s) and electrically conductive layer structure(s), inparticular formed by applying mechanical pressure, if desired supportedby thermal energy. The mentioned stack may provide a plate-shapedcomponent carrier capable of providing a large mounting surface forfurther components and being nevertheless very thin and compact. Theterm “layer structure” may particularly denote a continuous layer, apatterned layer or a plurality of non-consecutive islands within acommon plane.

In an embodiment, the component carrier is shaped as a plate. Thiscontributes to the compact design, wherein the component carriernevertheless provides a large basis for mounting components thereon.Furthermore, in particular a naked die as example for an embeddedelectronic component, can be conveniently embedded, thanks to its smallthickness, into a thin plate such as a printed circuit board.

In an embodiment, the component carrier is configured as one of thegroup consisting of a printed circuit board, and a substrate (inparticular an IC substrate).

In the context of the present application, the term “printed circuitboard” (PCB) may particularly denote a component carrier (which may beplate-shaped (i.e. planar), three-dimensionally curved (for instancewhen manufactured using 3D printing) or which may have any other shape)which is formed by laminating several electrically conductive layerstructures with several electrically insulating layer structures, forinstance by applying pressure, if desired accompanied by the supply ofthermal energy. As preferred materials for PCB technology, theelectrically conductive layer structures are made of copper, whereas theelectrically insulating layer structures may comprise resin and/or glassfibers, so-called prepreg or FR4 material. The various electricallyconductive layer structures may be connected to one another in a desiredway by forming through-holes through the laminate, for instance by laserdrilling or mechanical drilling, and by filling them with electricallyconductive material (in particular copper), thereby forming vias asthrough-hole connections. Apart from one or more components which may beembedded in a printed circuit board, a printed circuit board is usuallyconfigured for accommodating one or more components on one or bothopposing surfaces of the plate-shaped printed circuit board. They may beconnected to the respective main surface by soldering. A dielectric partof a PCB may be composed of resin with reinforcing fibers (such as glassfibers).

In the context of the present application, the term “substrate” mayparticularly denote a small component carrier having substantially thesame size as a component (in particular an electronic component) to bemounted thereon. More specifically, a substrate can be understood as acarrier for electrical connections or electrical networks as well ascomponent carrier comparable to a printed circuit board (PCB), howeverwith a considerably higher density of laterally and/or verticallyarranged connections. Lateral connections are for example conductivepaths, whereas vertical connections may be for example drill holes.These lateral and/or vertical connections are arranged within thesubstrate and can be used to provide electrical and/or mechanicalconnections of housed components or unhoused components (such as baredies), particularly of IC chips, with a printed circuit board orintermediate printed circuit board. Thus, the term “substrate” alsoincludes “IC substrates”. A dielectric part of a substrate may becomposed of resin with reinforcing spheres (such as glass spheres).

In an embodiment, the at least one electrically insulating layerstructure comprises at least one of the group consisting of resin (suchas reinforced or non-reinforced resins, for instance epoxy resin orBismaleimide-Triazine resin, more specifically FR-4 or FR-5), cyanateester, polyphenylene derivate, glass (in particular glass fibers,multi-layer glass, glass-like materials), prepreg material, polyimide,polyamide, liquid crystal polymer (LCP), epoxy-based Build-Up Film,polytetrafluoroethylene, a ceramic, and a metal oxide. Reinforcingmaterials such as webs, fibers or spheres, for example made of glass(multilayer glass) may be used as well. Although prepreg or FR4 areusually preferred, other materials may be used as well. For highfrequency applications, high-frequency materials such aspolytetrafluoroethylene (PTFE), liquid crystal polymer and/or cyanateester resins may be implemented in the component carrier as electricallyinsulating layer structure.

In an embodiment, the at least one electrically conductive layerstructure comprises at least one of the group consisting of copper,aluminum, nickel, silver, gold, palladium, and tungsten. Although copperis usually preferred, other materials or coated versions thereof arepossible as well, in particular coated with supra-conductive materialsuch as graphene.

In an embodiment, the component carrier is a laminate-type body. In suchan embodiment, the component carrier is a compound of multiple layerstructures which are stacked and connected together by applying apressing force, if desired accompanied by heat.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the component carrier can be better understood withreference to the following drawings. The elements and features in thedrawings are not necessarily to scale, emphasis instead being placedupon clearly illustrating the structures and principles of operation ofthe assemblies.

FIG. 1, FIG. 2 and FIG. 3 illustrate cross-sectional views of pre-formsof component carriers manufactured according to exemplary embodiments.

FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 illustrate cross-sectionalviews of structures obtained during manufacturing a component carrier,shown in FIG. 8, according to an exemplary embodiment.

FIG. 9, FIG. 10, FIG. 11 and FIG. 12 illustrate cross-sectional views ofstructures obtained during manufacturing a component carrier accordingto another exemplary embodiment.

FIG. 13 and FIG. 14 illustrate a cross-sectional view and a plan view ofa component carrier according to another exemplary embodiment.

FIG. 15 illustrates a cross-sectional view of a component carrieraccording to another exemplary embodiment.

FIG. 16 illustrates a cross-sectional view of a component carrieraccording to still another exemplary embodiment.

FIG. 17, FIG. 18, FIG. 19 and FIG. 20 illustrate cross-sectional viewsof structures obtained during manufacturing a component carrieraccording to another exemplary embodiment.

FIG. 21 illustrates a cross-sectional view of three component carriersarranged side by side according to another exemplary embodiment.

FIG. 22 illustrates an example showing a light-emitting diode emittinglight through transparent material.

FIG. 23, FIG. 24 and FIG. 25 show different structures obtained duringmanufacturing a component carrier according to an exemplary embodimentwhich is shown, in operation, in FIG. 26.

FIG. 27 illustrates spectacles according to an exemplary embodimentcomprising the component carrier shown in FIG. 26.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

The illustrations in the drawings are schematically presented. Indifferent drawings, similar or identical elements are provided with thesame reference signs.

The aspects defined above and further aspects of the invention areapparent from the examples of embodiment to be described hereinafter andare explained with reference to these examples of embodiment.

Before, referring to the drawings, exemplary embodiments will bedescribed in further detail, some basic considerations will besummarized based on which exemplary embodiments of the invention havebeen developed.

According to an exemplary embodiment, a component carrier with anembedded component having a lateral opening is provided. Exposing thecomponent on one side has the advantage that new opportunities forembedding are made possible. For instance, plug in connections as wellas optical connections can be accomplished in this way. Thus, it becomespossible to expose embedded components from a component carrier withhigh spatial accuracy at the side wall of the component.

A gist of an exemplary embodiment is that an embedded component can beexposed at a flange face thereof with high positional accuracy.Advantageously, the manufacturing method may be configured so that thecomponents to be exposed at a side surface thereof shall preferably notbe covered with resin there. In one embodiment, it may be ensured thatthe side wall surface of the embedded component remains free of anymaterial. This may be for instance accomplished by using channels orhollow spaces around the embedded component using no-flow prepreg orlow-flow prepreg for lamination. In another embodiment, the side wallmay be temporarily covered with sacrificial material of such a kind thatit can be selectively and easily removed later by carrying out simpletechnical methods. For instance, a release material paste may bearranged next to the component which fixes the component in place at adesired position. However, the material of the release material pastemay be easily removed (for instance by stripping) after having removedmaterial of the stack of electrically conductive layer structures and/orelectrically insulating layer structures for exposing the side wall. Allthese concepts have in common that they allow an exposure of a side wallof a component embedded in component carrier material with highprecision. Such a manufacturing architecture increases the flexibilityof designing component carrier type modules with improved functionality.

FIG. 1 illustrates a cross-sectional view of a pre-form of a componentcarrier 100, which is here embodied as a printed circuit board (PCB),manufactured according to an exemplary embodiment.

The plate-shaped laminate-type component carrier 100 which can beseparated from the structure of FIG. 1 comprises a laminated stack 102of component carrier material comprising a plurality of electricallyconductive layer structures 104 (here embodied as patterned metal foilsand metal vias, both preferably made of copper) and a plurality ofelectrically insulating layer structures 106 (here embodied as resinlayers, in particular epoxy based resin layers, with reinforcing fibers,in particular glass fibers, for example prepreg).

Moreover, the component carrier 100 comprises an electronic component108, which may for instance be a semiconductor chip. The electroniccomponent 108 may be electrically coupled with an electronic environmentvia the electrically conductive layer structures 104. The component 108is embedded in the component carrier material of the stack 102.According to FIG. 1, a side wall 110 of the component 108 is stillsurrounded by material of the stack 102. However, a milling tool 121 isshown in FIG. 1 which is currently in the process of removing materialof the stack 102 on the right-hand side of the milling tool 121 fromremaining material of the stack 102 on the left-hand side of the millingtool 121. As a result of this milling procedure, a component carrier 100is obtained having an embedded component 108 with an exposed side wall110. More specifically, the side wall 110 of the component 108 isexposed with regard to an environment of the component carrier 100 afterseparation by milling, so that the side wall 110 then forms part of anexterior lateral side wall of the component carrier 100.

The component carrier 100 manufactured according to FIG. 1 can beobtained by firstly cutting cavities (see reference numeral 122 in FIG.4) in a core 123 (i.e. fully cured resin material of the electricallyinsulating layer structures 106) as accommodation volumes for components108. As can be taken from a detail 131 in FIG. 1, the dimension of thecavities may be selected so that a gap 126 (between side wall 110 ofcomponent 108 and accommodation cavity delimiting side wall 112 of stack102) having a dimension, D, of for instance 500 μm thickness remainsafter placing the components 108 in the cavities on the right-hand sideaccording to FIG. 1. In contrast to this, a further gap 129 on theopposing other side of the component 108, i.e. on the left-hand sideaccording to FIG. 1, may have a significantly smaller dimension of, forinstance, 75 μm. This increases the accuracy of the positional placementof the component 108 in the component carrier 100. Thereafter, atemporary carrier (for instance a sticky tape) may be placed on a bottomsurface of the core 123 for closing the cavities at a bottom side.Thereafter, the components 108 are fixed in the cavities and on thetemporary carrier. A dielectric layer on top of the component 108 aswell as on top of the core 123 may then be laminated from an upper side.The said dielectric layer may be made preferably of no-flow prepreg orlow-flow prepreg in order to prevent filling of the mentioned gaps 126,129 during lamination by prepreg material melting during lamination andflowing into the respective gap 126, 129. Such a flow of resin isdisabled or at least strongly suppressed when using no-flow prepreg orlow-flow prepreg above and below gaps 126, 129. This prevention of flowof resin material in particular into the gap 126 strongly simplifiessubsequent exposure of the side wall 110 of the component 108 bymilling. Since the gap 126 remains free of resin, the side wall 110 ofthe component 108 is free of resin after the exposing procedure.

FIG. 2 illustrates a cross-sectional view of a pre-form of a componentcarrier 100 manufactured according to another exemplary embodiment.

The embodiment of FIG. 2 differs from the embodiment of FIG. 1 in thatthe removal of material of the stack 102 for exposing side wall 110 ofembedded component 108 of component carrier 100 is carried out by lasercutting rather than by milling. Furthermore, the embodiment of FIG. 2differs from the embodiment of FIG. 1 in that the mentioned gap 126 isfilled with a release material paste, as sacrificial material 128,according to FIG. 2. The release material paste may be made of a waxymaterial or may be formed based on polytetrafluoroethylene (PTFE). Afterseparating the component carrier 100 from the electrically conductivelayer structures 104 as well as the electrically insulating layerstructures 106 on the right-hand side of schematically illustrated lasercutting tool 125, the sacrificial material 128 embodied as releasematerial paste may be easily removed due to its poor adhesion tocomponent carrier material and to the component 108. Thereafter, theside wall 110 of the component 108 is exposed from sacrificial material128 and then forms part of a lateral side surface of the componentcarrier 100.

More specifically, the component carrier 100 manufactured according toFIG. 2 can be obtained by firstly cutting cavities in core 123 asaccommodation volumes for components 108. The dimension of the cavitiesmay be selected so that gap 126 having a dimension of for instance 100μm thickness remains after placing the components 108 in the cavities onthe right-hand side according to FIG. 2. Thereafter, a temporary carrier(for instance a sticky tape) may be placed on a bottom surface of thecore 123 for closing the cavities from a bottom side. Thereafter, thecomponents 108 are fixed in the cavities and on the temporary carrier.The sacrificial material 128 in form of the release material paste maythen be inserted into the gap 126 of the cavity, for instance by awiper, and may be cured. The release material paste prevents resinmaterial from adhering to the side wall 110 of the component 108 to beexposed. The dielectric layer on top of the component 108 as well as ontop of the core 123 may be laminated from an upper side. The saiddielectric layer may be made of ordinary prepreg, no-flow prepreg orlow-flow prepreg. Filling of the mentioned gap 126 during lamination ishere prevented by the presence of the sacrificial material 128,regardless of the prepreg type used. The temporary carrier may then beremoved and a further lamination procedure may be carried out at abottom side (for instance using a further prepreg foil and a furthercopper foil).

The gap 126 filled with the sacrificial material 128 can then be openedby laser cutting using laser cutting tool 125, and the release materialpaste material may be stripped. By stripping the release material paste,side wall 110 is exposed. Since the sacrificial material 128 may beeasily removed out of the gap 126 after the laser cutting, the side wall110 of the component 108 is exposed and is in particular free of resinafter the exposing procedure.

FIG. 3 illustrates a cross-sectional view of a pre-form of a componentcarrier 100 manufactured according to still another exemplaryembodiment.

The embodiment according to FIG. 3 differs from the embodiment accordingto FIG. 2 in particular in that two different cavities are formed, i.e.firstly a cavity for sacrificial material 128 (such as release layermaterial) only, and after supply and curing of the sacrificial material128, a second cavity overlapping with the first cavity and beingconfigured for mounting a component 108 therein can be formed.

More specifically, the component carrier 100 manufactured according toFIG. 3 can be obtained by firstly cutting first cavities in core 123 asaccommodation volumes for sacrificial material 128. Thereafter, a firsttemporary carrier (for instance a sticky tape) may be placed on a bottomsurface of the core 123 for closing the first cavities from a bottomside. Thereafter, the sacrificial material 128 may be supplied to thefirst cavities and on the temporary carrier, for instance by a wiper.The sacrificial material 128 may then be cured. The temporary carriermay then be removed. Second cavities may then be cut in core 123overlapping with the first cavities as accommodation volumes forcomponents 108. A further temporary carrier (for instance a furthersticky tape) may be placed on a bottom surface of the core 123 with thesacrificial material 128 for closing the second cavities from a bottomside. Thereafter, the components 108 may be placed in the secondcavities juxtaposed to the cured sacrificial material 128. A laminationprocedure may be carried out (for instance using a prepreg foil and acopper foil) at a surface of the structure facing away from the secondtemporary carrier. The second temporary carrier may then be removed. Afurther lamination procedure may be carried out (for instance using afurther prepreg foil and a further copper foil).

The gap 126 filled with the sacrificial material 128 can then be openedby laser cutting using laser cutting tool 125, and the release materialpaste material may be stripped. By stripping the release material paste,a hollow space is formed on the left-hand side of the component 108according to FIG. 3, thereby exposing side wall 110. Since thesacrificial material 128 may be easily removed out of the gap 126 afterthe laser cutting, the side wall 110 of the component 108 is free ofresin after the exposing procedure.

Although not shown in the figures, the release material pasteconstituting the sacrificial material 128 according to FIG. 2 and FIG. 3may be substituted by other sacrificial material 128 being selectivelyremovable with regard to material of the components 108. For instance, awater-soluble material may be used as sacrificial material 128, forinstance a salt or an appropriate polymer (for instance polyvinylalcohol). The sacrificial material 128 may be removed to thereby exposethe side wall 110 of the components 108 by supply of water.

FIG. 4 to FIG. 8 illustrate cross-sectional views of structures obtainedduring manufacturing a component carrier 100, shown in FIG. 8, accordingto an exemplary embodiment. This embodiment is similar to the embodimentof the component carrier 100 of FIG. 1.

Referring to FIG. 4, a stack 102 of a core 123 of fully cured resin withreinforcing particles (for instance FR4) as electrically insulatinglayer structure 106 covered on both opposing main surfaces thereof witha respective one of two electrically conductive layer structures 104(here embodied as copper foils) is shown. An accommodation cavity 122 isformed as a through hole through the stack 102. The stack 102 isarranged on a temporary carrier 130, such as a sticky tape, so that anopen bottom of the accommodation cavity 122 is closed by a portion ofthe temporary carrier 130. Thereafter, a component 108 (such as a laserdiode for emitting electromagnetic radiation, a photodiode for detectingelectromagnetic radiation, or a sensor such as a chemo sensor) may beinserted into the accommodation cavity 122 of the stack 102 and may beattached to a surface of the temporary carrier 130. As can be taken fromFIG. 4, the component 108 is placed asymmetrically in the accommodationcavity 122 in a lateral direction so that a gap 126 between a side wall110 of the component 108 and an accommodation cavity delimiting sidewall 112 of the stack 102 on the right-hand side has a width, D, beinglarger than another gap 129 between another side wall 110 of thecomponent 108 and another accommodation cavity delimiting side wall 112of the stack 102 on the left-hand side which has a width, d (d<D). Forinstance, the size D may be 500 μm, whereas the size d may be 75 μm.

Referring to FIG. 5, a further electrically insulating layer structure106 (here embodied as a prepreg sheet made of low-flow material orno-flow material) and a further electrically conductive layer structure104 (here embodied as a further copper foil) are attached to an uppermain surface of the structure shown in FIG. 4, i.e. to a surface facingaway from the temporary carrier 130. The low-flow prepreg or no-flowprepreg of which the said electrically insulating layer structure 106 ismade ensures that substantially no resin re-melts and flows into the gap126 during a lamination procedure. Thus, the two additionally appliedlayer structures 106, 104 may be connected with the structure shown inFIG. 4 by lamination, i.e. the application of pressure and heat, withoutthe risk that resin flows into gap 126 and covers side wall 110 ofcomponent 108 there. As a result, in particular the gap 126 remains openeven during lamination due to the use of low-flow prepreg or no-flowprepreg, which significantly simplifies exposing side wall 110 of thecomponent 108 later (see FIG. 8).

Referring to FIG. 6, a structure is shown which is obtained by firstlyremoving the temporary carrier 130 of FIG. 5 after the describedlamination procedure, and by secondly carrying out a further laminationprocedure at a bottom side. More specifically, the temporary carrier 130is no longer needed to provide mechanical support after the describedfirst lamination procedure during which the low-flow or no-flow resinmaterial of the further electrically insulating layer structure 106 hasbeen hardened. Consequently, the temporary carrier 130 may be removed,for instance may be peeled off from the rest of the structure shown inFIG. 5. Thereafter, a further electrically insulating layer structure106 (preferably made of low-flow prepreg or no-flow prepreg as well) anda further electrically conductive layer structure 104 (for example afurther copper foil) may be laminated to a lower main surface of thestructure shown in FIG. 5 after removal of the temporary carrier 130.Due to the use of low-flow prepreg or no-flow prepreg for theelectrically insulating layer structures 106 above and beneath thecomponent 108 and the gap 126, a hollow space 183 remains in an interiorof the structure shown in FIG. 6, and allows keeping side wall 110 ofcomponent 108 free of resin material.

Referring to FIG. 7, schematically shown milling tool 121 may operate onthe structure shown in FIG. 6 and may cut away a portion of the layerstack on the right-hand side of the milling tool 121 in FIG. 7 bymilling through the gap 126 or hollow space 183.

Referring to FIG. 8, the material of the stack 102 on the right-handside of milling tool 121 in FIG. 7 has been removed to thereby exposethe side wall 110 of the component 108 with regard to an environment ofthe component carrier 100.

When the component 108 is for instance embodied as laser diode, lightcan be emitted via the exposed side wall 110 to the environment. Whenthe component 108 is for instance embodied as photodiode, lightimpinging on the exposed side wall 110 from an environment may bedetected by the component 108. When the component 108 is for instance achemical sensor, a chemical in an environment of the exposed side wall110 can be detected by the component 108.

As a result of the described manufacturing procedure, the PCB typeplate-shaped laminated component carrier 100 according to FIG. 8 isobtained which comprises the stack 102 comprising multiple electricallyconductive layer structures 104 and multiple electrically insulatinglayer structures 106 as well as the component 108 embedded in the stack102. The side wall 110 of the component 108 is exposed with regard to anenvironment of the component carrier 100 so as to be functionallycoupleable with the environment of the component carrier 100. Accordingto FIG. 8, the exposed side wall 110 of the component 108 and a sidewall 133 of the stack 102 are aligned to form a substantially continuousside wall 110 of the component carrier 100 extending substantiallyvertically. While one main surface 120 of the cuboid component 108 isexposed at side wall 110, the other five main surfaces of this component108 are covered by component carrier material of the stack 102 so as tobe properly mechanically and electrically secured and protected.

FIG. 9 to FIG. 12 illustrate cross-sectional views of structuresobtained during manufacturing a component carrier 100 according toanother exemplary embodiment. This embodiment is similar to theembodiments of the component carriers 100 of FIG. 2 and FIG. 3.

Referring to FIG. 9, a structure similar to that shown in FIG. 4 isformed.

In order to obtain the structure shown in FIG. 10, the gap 126 on theright-hand side of FIG. 9 spacing the component 108 with regard to anaccommodation cavity delimiting side wall 112 of the stack 102 is filledwith a removable sacrificial material 128. For instance, the sacrificialmaterial 128 may be embodied as a release structure with non-adhesiveproperties with regard to the material of the component 108. Such arelease structure may for instance be a waxy component (which may bebased on calcium stearate) or a PTFE-based material which can be appliedin the form of a paste by using a wiper (not shown). The releasestructure may have the property to be non-adhesive with regard to bothcomponent material and component carrier material, in particular copper,epoxy resin, reinforcing glass fibers, and silicon. If desired orrequired, the sacrificial material 128 may be cured after insertion intogap 126, for instance by a thermal treatment, by a chemical treatmentand/or by applying mechanical pressure.

After having filled the cavity 126 with the sacrificial material 128, adielectric sheet as further electrically insulating layer structure 106(here embodied as at least partially uncured material, for instance aprepreg sheet) and a further electrically conductive layer structure 104(here embodied as a further copper foil) are attached to an upper mainsurface of the structure shown in FIG. 9, i.e. to a surface facing awayfrom the temporary carrier 130. In particular, the “at least partiallyuncured material” may comprise or consist of B-stage material and/orA-stage material. By providing the layer stack with prepreg or any otherB-stage material, at least a portion of the layer stack may re-meltduring lamination so that resin (or the like) may flow forinterconnecting the various elements and for closing gaps or voids andmay therefore contribute to a stable intrinsic interconnection withinthe component carrier 100 being manufactured. Subsequently, the twoadditionally applied layer structures 106, 104 may be connected with thestructure shown in FIG. 9 by lamination, i.e. the application ofpressure and heat. While resin of the at least partially uncuredmaterial of the electrically insulating layer structure 106 may flow ingap 129 and may at least partially fill the latter during lamination,such flowable resin material will not move into gap 126 because gap 126has already been filled by the sacrificial material 128. Thisadvantageously keeps also the side wall 110 of the component 108 coveredby sacrificial material 128 free of resin material.

Referring to FIG. 11, a structure is shown which is obtained by firstlyremoving the temporary carrier 130 of FIG. 9 after the describedlamination procedure, and by secondly carrying out a further laminationprocedure from a bottom side. More specifically, the temporary carrier130 is no longer needed to provide mechanical support after thedescribed first lamination procedure during which the previously atleast partially uncured material of the further electrically insulatinglayer structure 106 has become hardened. Secondly, a furtherelectrically insulating layer structure 106 and a further electricallyconductive layer structure 104 are laminated onto the structure shown inFIG. 10 (without temporary carrier 130) from a bottom side, to therebyobtain a symmetric configuration in a vertical direction.

Referring to FIG. 12, a portion of the obtained structure on the righthand side of the component 108 is then removed by laser cutting, asindicated schematically by reference numeral 125. A laser cutting lineis oriented to extend vertically through the sacrificial material 128.Advantageously, the laser process has a relatively high tolerance ordoes not need to be carried out with high spatial accuracy, since therelatively large width, D, of the gap 126 filled with the sacrificialmaterial 128 defines the allowed tolerance.

The result of the laser cutting procedure will be a component carrier100 having substantially an appearance as shown in FIG. 8. In order toobtain such a component carrier 100, the sacrificial material 128exposed after laser cutting is removed (for instance by stripping) tothereby expose the side wall 110. Such a removal process is very simpledue to the intentionally poor adhesion between the sacrificial material126 on the one hand and the component 108 and component carrier material102 on the other hand.

In another embodiment, the procedure described referring to FIG. 9 toFIG. 12 may be carried out in a corresponding way, however substitutingthe release paste material by other material for sacrificial structure128, preferably a water-soluble material such as a salt. When arrivingat a structure corresponding to FIG. 12, this water-soluble material maybe removed by supplying water, to thereby expose side wall 110 ofcomponent 108.

FIG. 13 and FIG. 14 illustrate a cross-sectional view and a plan view ofa component carrier 100 according to an exemplary embodiment. FIG. 14shows a cutting line 141 along which the illustration of FIG. 14 is tobe cut to arrive at the cross-sectional view of FIG. 13. According toFIG. 13 and FIG. 14, a slit-shaped access recess 114 contributing toexposing the side wall 110 extends from upper main surface 116 of thecomponent carrier 100 to be manufactured up to a lower main surface 118thereof. As can be taken from FIG. 14, the slit has a length L beinglarger than a width W thereof. The length L direction corresponds to adirection extending parallel to the side wall 110 of the component 108,whereas the width W direction corresponds to a direction extendingperpendicular to the side wall 110 of the component 108. In the shownembodiment, the access recess 114 is configured as a through-holeextending through the entire stack 102. According to FIG. 13 and FIG.14, sacrificial material 128 is again foreseen as a selectivelyremovable spacer between side wall 110 of component 108 and cavitydelimiting side wall 112 of stack 102. However, in other embodiments inwhich a side wall 110 of component 108 is selectively exposed by a slitcut, the sacrificial material 128 may also be omitted (as in FIG. 1,FIG. 4 to FIG. 8). When sacrificial material 128 is however foreseen,the sacrificial material 128 may be removed selectively after havingformed the slit-shaped access recess 114 (for instance by directingwater through the slit-shaped access recess 114 for removingwater-soluble sacrificial material 128). It is also possible that atleast part of the sacrificial material 128 is already removed duringslit formation. In order to relax the accuracy requirements for formingthe slit-shaped access recess 114 (for instance by milling or lasercutting), it is possible also according to FIG. 13 and FIG. 14 that thecomponent 108 is arranged laterally asymmetrically in accommodationcavity 122 of the stack 102 with different distances d<D with regard toopposing accommodation cavity delimiting side walls 112 of the stack102. The distance, D, at the side where the formation of the slit-shapedaccess recess 114 occurs is preferably larger than the distance, d, onthe other side.

FIG. 15 illustrates a cross-sectional view of a component carrier 100according to another exemplary embodiment. According to the embodimentof FIG. 15, a lateral access recess 114 extending into the stack 102 andexposing the side wall 110 of component 108 extends from a lateral sidewall 133 of the stack 102 up to the side wall 110 of the component 108.In FIG. 15, the access recess 114 is configured as a blind hole.

According to FIG. 15, a further component 124, which is here configuredas a light guide or optical fiber, is inserted into the blind hole typeaccess recess 114. When the component 108 is for instance embodied as alight detecting element (for instance a photodiode), electromagneticradiation 143 propagating along the component 124 up to the exposed sidewall 110 of the component 108 can be detected by component 108. When thecomponent 108 is however embodied as a light emitting element (forinstance a laser diode), electromagnetic radiation 145 can be injectedinto the optical fiber for propagation along the component 124 via theexposed side wall 110 of the component 108. Thus, the component carrier100 of FIG. 15 may for instance be used for optoelectronic datatransmission.

FIG. 16 illustrates a cross-sectional view of a component carrier 100according to still another exemplary embodiment. According to FIG. 16,slit-shaped access recess 114 is embodied as a blind hole exposing twoopposing side walls 110 of a component 108 and a further component 124both embedded in the same component carrier 100. Recess 114 spacescomponents 108, 124 and simultaneously enables wireless datacommunication by transmission of electromagnetic radiation 147 (such asinfrared radiation, optical light, radiofrequency (RF) radiation, etc.)between the exposed side walls 110 of the components 108, 124 via an airgap provided by access recess 114. Thus, the component 108 and thefurther component 124 being both embedded in the stack 102 arecommunicatively coupled for wireless data communication via the accessrecess 114. For instance the component 108 may be an electromagneticradiation emitter and the further component 124 may be anelectromagnetic radiation detector.

In contrast to FIG. 1 to FIG. 3, the side walls 110 of the components108, 124 are mutually exposed in an interior of the component carrier100 so that the side walls 110 form part of an interior (rather thanexterior) lateral side wall of the component carrier 100.

FIG. 17 to FIG. 20 illustrate cross-sectional views of structuresobtained during manufacturing a component carrier 100 according toanother exemplary embodiment.

A structure shown in FIG. 17 is obtained by forming a first cavityportion 151 in stack 102, for instance as a through hole in a fullycured core. A temporary carrier 130, such as a sticky tape, is attachedto a lower main surface of the stack 102 and closes the through hole atthe bottom side. Subsequently, the first cavity portion 151 is filledwith sacrificial material 128 such as release material. If desired orrequired, the sacrificial material 128 may then be cured. Thereafter,temporary carrier 130 may be removed.

A structure shown in FIG. 18 is obtained by subsequently forming asecond cavity portion 153 as a further through hole in the structureaccording to FIG. 17 without temporary carrier 130. The second cavityportion 153 is formed so as to laterally overlap with the first cavityportion 151. As a result, part of the sacrificial material 128 isremoved when forming the second cavity portion 153.

A structure shown in FIG. 19 is obtained by connecting a furthertemporary carrier 130′ to a lower main surface of the stack 102, to alower main surface of the remaining sacrificial material 128 and toclose a bottom of the through hole constituting the second cavityportion 153. Thereafter, component 108 is inserted into the secondcavity portion 153 so that the first cavity portion 151 filled with thesacrificial material 128 and the second cavity portion 153 accommodatingthe component 108 together constitute a common accommodation cavity 122for accommodating the component 108 and the sacrificial material 128.

A structure shown in FIG. 20 is obtained by laminating a further portionof stack 102 onto an upper main surface of the structure shown in FIG.19. Thereafter, the further temporary carrier 130′ may be removed from abottom surface of the obtained structure. After this, yet anotherportion of stack 102 can be laminated on a lower main surface of theobtained structure. As indicated by a separation line 155, the obtainedstructure may be separated then by a vertical cut, which can forinstance be accomplished by a laser treatment or mechanically. Afterremoving the remaining portion of the sacrificial material 128, the sidewall 110 of component 108 is exposed and a component carrier 100according to an exemplary embodiment is obtained.

The embodiment of FIG. 17 to FIG. 20 has the advantage that there issubstantially no limitation concerning the horizontal width of the firstcavity portion 151 which simplifies the supply of the sacrificialmaterial 128 into the first cavity portion 151.

FIG. 21 illustrates a cross-sectional view of three component carriers100 spaced side-by-side according to another exemplary embodiment.

In the embodiment of FIG. 21, the juxtaposed component carriers 100 arespaced with regard to each other by respective gaps 197. Lateral surfaceportions of multiple embedded components 108 of the component carriers100 are exposed. As can be taken from FIG. 21, each of the showncomponent carriers 100 comprises, as respective component 108, at leastone sender 108 a and at least one receiver 108 b.

By arranging the component carriers 100 one next to the other withmutually aligned sender 108 a of one component carrier 100 emittingelectromagnetic radiation 199 and receiver 100 b of another componentcarrier 100 receiving the electromagnetic radiation 199, the arrangementaccording to FIG. 21 is appropriate for applications such as Near FieldCommunication (NFC). A communication according to another communicationprotocol is possible. For instance, the communication may beaccomplished by infrared communication, Bluetooth®, etc. The componentcarrier 100 being arranged, according to FIG. 21, in the middle betweenthe other two component carriers 100 has a respective pair of sender 108a and receiver 108 b on each of the two opposing main surfaces thereof.Thus, the component carrier 100 in the middle sandwiched by the othertwo component carriers 100 may communicate with both other componentcarriers 100. Bluetooth® is a registered trademark of Bluetooth Sig,Inc. of Kirkland, Wash., U.S.A.

FIG. 22 illustrates an example showing a light-emitting diode 200emitting light 202 through optically transparent material 204.

According to FIG. 22, the light-emitting diode 200 is encapsulated in anencapsulant 206 and emits the light 202 with a cross-sectional area Ainto the transparent material 204. Due to a rough surface of thetransparent material 204, light diffraction occurs which increases thecross-sectional area A′ of the light leaving the transparent material204 at an air interface. This undesired phenomenon is promoted by thepronounced surface roughness of the transparent material 204.

FIG. 23 to FIG. 25 show different structures obtained duringmanufacturing a component carrier 100 according to an exemplaryembodiment which is shown, in operation, in FIG. 26.

Referring to FIG. 23, a component 108 is embedded in a stack 102composed of electrically conductive layer structures 104 as well aselectrically insulating layer structures 106. In the shown embodiment,the component 108 comprises an electromagnetic radiation emitting member108′ (such as a light-emitting diode, for instance embodied as laserdie) configured for emitting light as electromagnetic radiation 145. Theelectromagnetic radiation emitting member 108′ is electrically coupledwith the electrically conductive layer structures 104. Theelectromagnetic radiation emitting member 108′ is circumferentiallycovered by a transparent material 108″. The transparent material 108″ ispreferably a fiber free resin which does not disturb propagation ofelectromagnetic radiation 145 (compare FIG. 26) through the transparentmaterial 108″. Thus, FIG. 23 shows an embedded component 108 in a panel.

Referring to FIG. 24, material of the stack 102 is removed by a cuttingprocedure, as described above, to thereby expose side wall 110 of thecomponent 108, more precisely the side wall 110 of the transparentmaterial 108″ of the component 108. During operation of the componentcarrier 100 being manufactured, electromagnetic radiation 145 emitted bythe electromagnetic radiation emitter member 108′ propagates through thetransparent material 108″ and leaves the component carrier 100 via theexposed side wall 110. However, as a result of the cutting procedure,the exposed side wall 110 has a pronounced surface roughness, asindicated schematically by reference numeral 210. Hence, FIG. 24 showsthe result of a card cutting procedure, after which the side surface ofthe transparent material 108″ remains rough.

Referring to FIG. 25, the exposed rough side wall 110 of the transparentmaterial 108″ is polished, for instance mechanically or chemically.Hence, the structure shown in FIG. 24 may be made subject of a lateralpolishing procedure which smoothes the side wall surface of thetransparent material 108″ after the polishing process. As a result, theemitted electromagnetic radiation 145 propagates as a parallel narrowbeam through the transparent material 145 and the side wall 110 withoutbeing substantially spatially widened, see FIG. 26.

The embodiment according to FIG. 26 has the advantage that it ispossible to embed a laser diode as electromagnetic radiation emittingmember 108′ in the PCB type component carrier 100, and at the same timeuse the transparent window in the stack 102 for propagation of the laserbeam as electromagnetic radiation 145. As can be taken from FIG. 26, theportion of the transparent material 108″ between the side wall of theelectromagnetic radiation emitting member 108′ and the lateral side wallof the component carrier 100 forms part of an optical path along whichthe electromagnetic radiation 145 propagates. Therefore, the componentcarrier 100 according to FIG. 26 can be used for optical communicationor projection, for example of visible light or infrared radiation, inparticular embodied as laser beam. The electromagnetic radiation 145 isemitted by the component 108 or can be received and detected by thecomponent 108. Preferably, the transparent material 108″ is free ofbubbles, fibers, fabrics, etc. and has absorption properties allowinglight passing without significant losses. As can be taken from FIG. 26,the transparent material 108″ remains in the lateral opening of thecomponent carrier 100. Although not shown in the figure, a photodiodemay be installed in the back of the laser diode. A person skilled in theart of laser technology will understand the installation of thephotodiode in the build up with the methods mentioned in the abovedescription. As an alternative to the embodiment according to FIG. 26,it is also possible to keep the lateral opening of the component carrier100 (filled with the transparent material 108″ according to FIG. 26)empty or to remove transparent material 108″ out of such a lateralopening, similar as in FIG. 15.

FIG. 27 illustrates spectacles 220 according to an exemplary embodimentcomprising the component carrier 100 shown in FIG. 26.

Descriptively speaking, FIG. 27 schematically illustrates a left half ofthe spectacles 220 (see symmetry axis 212). As can be taken from FIG.27, the component carrier 100 according to FIG. 26 is assembled within ahousing 216 which may be connected to an arm or a frame of thespectacles 220 (see reference numeral 218). As also shown in FIG. 27,the spectacles 200 additionally comprise a screen 230 onto which a userwearing the spectacles 220 looks with his eyes 240. The lighttransmitted as the electromagnetic radiation 145 from theelectromagnetic radiation emitting member 108′ of the component 108embedded within the component carrier 100 is displayed on the screen 230and can be seen by the user when wearing and looking through thespectacles 220. The screen 230 can have micro-actuators andmicro-mirrors for means of light deflection and image formation. Colorscan be formed with three lasers in red, green and blue to form the RGBsystem of colors.

It should be noted that the term “comprising” does not exclude otherelements or steps and the “a” or “an” does not exclude a plurality. Alsoelements described in association with different embodiments may becombined.

It should be further understood that when the phrase “at least one of Aand B” is included in a claim, where the labels A and B represent arecitation of limitations or features, the phrase “at least one of A andB” means at least one of A or B. It should be further understood that“at least one of A or B” includes the limitations or features of: Aalone; B alone; any positive whole number of A alone; any positive wholenumber of B alone; and any combination of a positive whole number of Awith a positive whole number of B.

Implementation is not limited to the preferred embodiments shown in thefigures and described above. Instead, a multiplicity of variants arepossible which use the solutions shown and the principle according toembodiments of the invention even in the case of fundamentally differentembodiments.

We claim:
 1. A component carrier, wherein the component carriercomprises: a stack comprising a plurality of electrically conductivelayer structures and/or electrically insulating layer structures; acomponent embedded in the stack; wherein at least a portion of a sidewall of the component is exposed.
 2. The component carrier according toclaim 1, wherein the side wall of the component is exposed with regardto an environment of the component carrier.
 3. The component carrieraccording to claim 1, wherein the exposed side wall and an adjacent sidewall of the stack are aligned to form a substantially continuous sidewall of the component carrier.
 4. The component carrier according toclaim 1, wherein an access recess in the stack exposing the side wall ofthe component extends from a lateral side wall of the stack up to theside wall of the component.
 5. The component carrier according to claim1, wherein an access recess in the stack exposing the side wall of thecomponent extends from one of two opposing main surfaces of the stack atleast up to the component.
 6. The component carrier according to claim4, wherein the access recess is a slit having a length in a directionextending parallel to the side wall of the component, being larger thana width in a direction extending perpendicular to the side wall of thecomponent.
 7. The component carrier according to claim 4, wherein theaccess recess is configured as one of the group consisting of athrough-hole extending through the entire stack, and a blind holeextending at least up to the component.
 8. The component carrieraccording to claim 6, further comprising at least one of the followingfeatures: wherein only one main surface of the component is exposed,whereas all other main surfaces of the component are covered by materialof the stack; wherein the component is arranged laterally asymmetricallyin an accommodation cavity of the stack with different distances withregard to opposing accommodation cavity delimiting side walls of thestack; wherein the component comprises a sensor configured for sensingsensor information via the exposed side wall; wherein the componentcomprises an electromagnetic radiation source configured for emittingelectromagnetic radiation via the exposed side wall; a further componentembedded in the stack and having at least a portion of a side wallexposed with regard to the side wall of the component so that thecomponent and the further component are communicatively coupled with oneanother at least partially via a common access recess between the sidewalls, wherein the component and the further component are configured asat least one pair of the group consisting of an electromagneticradiation emitter and an electromagnetic radiation detector, a lightguide and a light emitter, and a light guide and a light detector;wherein at least one of the electrically insulating layer structuresclosest to the embedded component is made of low-flow prepreg or no-flowprepreg; wherein the component is selected from a group consisting of anelectronic component, an electrically non-conductive and/or electricallyconductive inlay, a heat transfer unit, a light guiding element, anenergy harvesting unit, an active electronic component, a passiveelectronic component, an electronic chip, a storage device, a filter, anintegrated circuit, a signal processing component, a power managementcomponent, an optoelectronic interface element, a voltage converter, acryptographic component, a transmitter and/or receiver, anelectromechanical transducer, an actuator, a microelectromechanicalsystem, a microprocessor, a capacitor, a resistor, an inductance, anaccumulator, a switch, a camera, an antenna, a magnetic element, afurther component carrier and a logic chip; wherein at least one of theelectrically conductive layer structures comprises at least one of thegroup consisting of copper, aluminum, nickel, silver, gold, palladium,and tungsten, any of the mentioned materials being optionally coatedwith supra-conductive material such as graphene; wherein at least one ofthe electrically insulating layer structures comprises at least one ofthe group consisting of resin, reinforced or non-reinforced resin, forinstance epoxy resin or Bismaleimide-Triazine resin, FR-4, FR-5, cyanateester, polyphenylene derivate, glass, prepreg material, polyimide,polyamide, liquid crystal polymer, epoxy-based Build-Up Film,polytetrafluoroethylene, a ceramic, and a metal oxide; wherein thecomponent carrier is shaped as a plate; wherein the component carrier isconfigured as one of the group consisting of a printed circuit board,and a substrate; configured as a laminate-type component carrier;wherein the exposed side wall forms part of one of an exterior lateralside wall of the component carrier, and an interior lateral side wall ofthe component carrier; wherein the component comprises anelectromagnetic radiation emitting member configured for emittingelectromagnetic radiation and being at least partially covered by atransparent material at least partially forming the exposed side walland being transparent for the electromagnetic radiation emitted by theelectromagnetic radiation emitter member, wherein at least part of thetransparent material at least partially forming the exposed side wall ispolished.
 9. A method of manufacturing a component carrier, the methodcomprising: forming a stack of a plurality of electrically conductivelayer structures and/or electrically insulating layer structures;embedding a component in the stack; and subsequently removing materialof the stack to thereby expose at least a portion of a side wall of thecomponent with regard to an environment of the component carrier. 10.The method according to claim 9, wherein embedding the component in thestack further comprises forming an accommodation cavity in at least oneof the layer structures of the stack and placing the component in theaccommodation cavity asymmetrically in a lateral direction.
 11. Themethod according to claim 10, wherein the component is placed in theaccommodation cavity so that a size of a gap between a side wall of thecomponent and an accommodation cavity delimiting side wall of the stackis different from a further size of a further gap between an opposingfurther side wall of the component and an opposing further accommodationcavity delimiting side wall of the stack.
 12. The method according toclaim 9, the method further comprising: filling at least part of a gapbetween the component and an accommodation cavity delimiting side wallof the stack with a removable sacrificial material; and at leastpartially removing the sacrificial material after completion of theembedding to thereby expose the side wall.
 13. The method according toclaim 12, further comprising: inserting the component in a first part ofthe accommodation cavity, and subsequently filling the sacrificialmaterial into at least part of a remaining second part, as the gap, ofthe accommodation cavity laterally juxtaposed to the first part.
 14. Themethod according to claim 12, further comprising: forming a first cavityportion in the stack and filling the first cavity portion at leastpartially with the sacrificial material, and subsequently forming asecond cavity portion in the stack overlapping with the first cavityportion and inserting the component into the second cavity portion sothat the first cavity portion at least partially filled with thesacrificial material and the second cavity portion accommodating thecomponent together constitute the accommodation cavity; wherein thesacrificial material comprises one of the group consisting of a releasestructure with non-adhesive properties with regard to the material ofthe stack and the component, an evaporable liquid, a flushable liquid,and a water soluble substance.
 15. The method according to claim 9,further comprising: providing the component with a removable sacrificialmaterial thereon prior to the embedding; subsequently embedding thecomponent with the removable sacrificial material thereon into thestack; at least partially removing the sacrificial material aftercompletion of the embedding to thereby expose the side wall.
 16. Themethod according to claim 9, comprising at least one of the followingfeatures: removing the material of the stack comprises at least one ofthe group consisting of milling and laser cutting; a size of a lateralgap between the component and an accommodation cavity delimiting sidewall of the stack is in a range between 5 μm and 500 μm; embedding thecomponent comprises laminating the component with the stack so that atleast partially uncured material of the layer structures is cured;forming the stack comprises attaching a temporary carrier to part of thelayer structures comprising at least partially uncured material, andremoving the temporary carrier from the stack after curing the at leastpartially uncured material of the layer structures.
 17. The methodaccording to claim 9, further comprising: embedding a component in thestack which component comprises an electromagnetic radiation emittingmember configured for emitting electromagnetic radiation and being atleast partially covered by a transparent material at least partiallyforming the exposed side wall and being transparent for theelectromagnetic radiation emitted by the electromagnetic radiationemitter member.
 18. The method according to claim 17, furthercomprising: after the removing, polishing at least part of thetransparent material at least partially forming the exposed side wall.19. The method according to claim 17, further comprising: assembling thecomponent carrier with a screen to form spectacles wearable by a user,wherein the electromagnetic radiation emitted by the electromagneticradiation emitter member is projected on the screen to be displayed tothe user.
 20. The method according to claim 19, wherein the screencomprises micro-actuators and micro-mirrors for deflection ofelectromagnetic radiation and image formation.